Cleanup plan revised for Sea-Tac Airport sites in Burien and SeaTac Comments sought; meeting set on plans for former apartments and Lora Lake

BURIEN – The Port of Seattle would remove or contain contaminated soil and
sediment on its property at the
former Lora
Lake Apartments in Burien and nearby at Sea-Tac Airport in SeaTac under
revisions to a proposed legal agreement between the port and the
Washington Department of Ecology.

Ecology is gathering public comments on the proposal and related documents
through June 17, 2015, and will hold a public meeting to explain and answer
questions about the draft plan.

Proposed cleanup plan
The draft agreement, called a consent decree, and cleanup plan reflect public
comments Ecology received on
earlier proposals, issued
in 2013. Work under the revised proposal would begin in 2017.

The contamination came from industrial activities that pre-dated construction
of the apartment complex, later purchased by the airport as part of a safety
zone for the Third Runway. Lora Lake is an artificial lake where groundwater
filled a former peat mine.

The proposal divides the cleanup – to be overseen by Ecology – into three
parts and includes these actions:

Former apartment complex: Remove highly
contaminated soil for disposal, place a cap (such as pavement)
over less-contaminated areas and place a deed restriction to
protect the cap and limit future use of the property to
commercial activities.

Lora Lake: Fill the lake with clean soil to
contain contaminated sediment, while re-establishing a former
wetland that will protect water quality in Miller Creek, which
passes nearby. Also, in response to public comments, remove a
small area of lightly contaminated soil just west of Lora Lake,
and adopt additional technical details for long term
post-cleanup monitoring of this area.

Dredged material containment area: Use
pavement or gravel to cover contaminated sediment deposited on
airport property from a past dredging of Lora Lake, with a deed
restriction to maintain this cover. This cover would also
include low-level contaminated soil expected to be removed from
the apartment complex site. Also, in response to public
comments, use a corrected map to ensure that this area is
outside the creek’s 100-year flood plain boundary.

Comment information
Ecology seeks public comment through June 17, 2015, on the proposal and related
documents:

The agreement, called a consent decree, to be filed in King
County Superior Court.

A cleanup action plan, to be filed as part of the consent
decree.

An environmental review, called a mitigated determination of
non-significance, conducted by Ecology under the State
Environmental Policy Act.

Additional information on Lora Lake Apartments site and the
draft cleanup action plan is available on an Ecology
fact sheet.

Companion stormwater project
A city of Burien storm drain conveys stormwater from a 78-acre area upstream
of the former apartment complex to Lora Lake. Burien proposes to re-route
this storm water to a Low Impact Development infiltration facility south of the
former apartment complex. Ecology has offered Burien a $1.45 million grant for
this work as part of a Water Quality Financial Assistance program.

The cleanup proposal includes an alternate stormwater management plan in case
the city stormwater project does not proceed.

Meeting information

May 13, 2015, 6 to 9 p.m.

Open house begins at 6 p.m.
Presentation begins at 7 p.m., followed by questions and answers.